Voltage regulator system



Dec. 20, 1949 DEBREY 2,491,802

'VOLTAGE REGULATOR SYSTEM Filed oct. 28, 1946 2 Sheets-Sheet l AZZernaior 7 a .93 a J26 99 92 96' 155; J76 ii g MichaeZ fle y M. DEBREY VOLTAGE REGULATOR SYSTEM Filed Oct. 28, l946 \V w e w w m a m .u L M M w I v z Patented Dec. 20, 1949 'ZAQLMZ UNITED STATES PATENT OFFICE VOLTAGE REGULATOR SYSTEM lvi'ichael Debrey, East Moline, Ill.

Application October 28, 1946, Serial No. 706,131

3 Claims. (Cl. 32228) My invention relates to the regulation of the output voltage of alternators, and in particular to a system employing a vibrating switch element which vibrates at a frequency materially below the synchronous frequency of the alternator.

In the prior art, in such regulating systems, the vibrating switch elements have been arranged to vibrate at the synchronous frequency of the alternator, and at such a high frequency there is a definite limit as to the size of alternator which can be so regulated. In such a regulator operating synchronously, as a practical matter, the control current broken by the vibrator contacts cannot exceed about one ampere without seriously damaging the contacts, and this corresponds to a comparatively small alternator, certainly not greater than 100 kw.

An of my invention is to provide a voltregulating system which is suitable for regulating alternators of relatively large size,

, nother object of my invention is to provide a i regulating system employing a nonn'onous electromagnetic vibrator which vi brates relatively slowly, of the order of 200 to 500 vibrations per minute.

'urther object of my invention is to provide e regulating system capable of handling currents of substantial value.

Still another object of my invention is to avoid the ourning of vibrator contacts in a voltage regulating system handling relatively large currents.

ention will be better understood by ref- '2 following specification and the apwings whereinis a circuit diagram of my regulating syst showing the circuit connections of the several elements,

Fig. 2 is a top plan view of the vibrating switch unit with parts in section, and

Fig. 3 is a front elevation of the vibrating switch unit, with parts in section, taken on the line 3--3 of 2.

In the low speed non-synchronous vibrator switch which I employ, he slow operation permits the contacts to become separated by an appreciable space, of the order of 0.02 inch or more, whe as in the synchronous vibrators operating at perhaps 720G vibrations per minute, the spacing between the contacts is often as small as 0.001 inch, which will are badly even on small values of current. In my system, the non-synchronous vibrator is provided with a supplementary damping w... ding and a ballast wheel, and is used in a circuit with a relay in such a way as to greatly improve the regulating action.

Referring to the drawings in detail, in Fig. 1, the alternator it; has output connections 19, 8t, a field winding ea. The alternator may be a .hase alternator, of which is and as are the terminals of one phase.

A direct current exciter 8d delivers its output to the field of the alternator i8, and the eXciter has its own field winding Hit. The exciter is self-excited, but a rheostat Iiii is connected in series with the exciter field. Provision is made for intermittently short circuiting the terminals of rheostat fill in a manner hereafter described, for the purpose of integratingly increasing the current passing through the exciter field and th eby raising the alternator output voltage WIT on it requires such regulation.

The vibrating switch element V is shown in stall in Figs. 2 and 3, and is more particularly described in my copending application Serial No. 703,409, filed October 15, 1946, now Patent No. 2,48%,934, issued October 18, 1949.

The vibrating switch element V comprises a magnetic frame 5, 6 which may be made in two pieces for convenience, in magnetic relation. A

rincipal actuating winding A is wound on laminated magnetic frame 5, G, and is connected to the output terminals of alternator 58 through binding posts 59, 5!, resistance i234, switch 124a, and leads '59, iii Rotatably mounted in a gap in magnetic frame 5, E3, is an armature 9 which is urged by an adjustable spring 55 out of the position of minimum reluctance which would be, to most closely line up with or approach engagement with pole faces l, 8, of frame 5, 6. A ballast wheel it having a web 45 is mounted on the shaft H! which fixedly carries armature 5i and materially increases the mechanical inertia of the vibrator unit and makes it impossible for it to have a natural frequency of vibration anywhere near as as '2200 per minute.

Fixedly carried on shaft i8 is also a block i! which fixedly carries in insulating relation an arm or finger i 9, and by a pivot 33 carries in pivotal and insulating relation another arm or finger 2B. A bumper roller 31 is pivotally carried by a pivot on arm Zil. A stop block 35 of insulating material is mounted on the frame and supported between arms iii and 20 and is positioned to be engaged by bumper roller 3! to cause relative separation of arms 5 t and 2t and the terminal contacts 2! and 22 respectively carried thereby when armature ii rotates block W. Arms l 9 and 2t": and their contacts are respectively connected to binding posts so and 553. A helical spring 2i is connected to bracket 29 carried by -ei Lil preferably has a threaded or cc to prevent it from sticking to It will be noted that pivot 33 is offset substantially with reference to the axis of shaft 19, w rich gives arm as a sliding motion with referto arm is when shaft iii rotates. Adjacent the sides arms iii an' as are positioned re, tively fiat spring blades 36 and Std which yiei ily roller 3? and arm is respectively if unusually powerful impulse is given to shaft ill, as by a sudden overload, and in such cases, the 5 serves to hold the contacts engaged.

5. substantially spaced separation of i and when shaft it is rotated, and not ly rubbing contact.

A supplementary damping winding ll is also wound on magnetic frame 5, 5, and may be wound in superposed relation over principal winding i. This supplementary winding ll is intermittently short-circuited in a manner below described and thereby varies the equivalent magnetic reluctance of the frame 5, 5. Supplementary winding is connected to terminals l5, 16, which in turn by wires H5, H3 are connected to the terminals ii l, H2 of a resistor IN adjustably tapped at iii. A signal lamp H8 is connected from a tap on resistor llfito connection H5 and serves to indicate by its flickering whether the vibrator is operating properly.

A relay R having an actuating winding 88 has an armature tit pivotally mounted at 92, carrying terminal contacts 93, 94, and also has fixed but adjustable contact 96 engageable with-movable contact S l when the winding 88 is energized, and also has stop 95 to restrain the upward motion of armature 98 when urged upward by spring $7 when winding 88 is deenergized. A condenser 330. may be connected across winding 88 to reduce surges, and undue sparking between contacts and 22. Movable contact 94 and fixed contact 95 are respectively connected by wires ll"! and lit; to terminal H4 and tap ill of resistor lid, so that the lower portion of resistor lid is shorted out of the circuit when winding is energized and armature S9 is pulled down, thus resulting in decreasing the short circuit resistance of supplementary winding H and thereby changing the equivalent magnetic reluctance of frame 5, 6.

Binding posts 58 and Bil are respectively con nected by wires 8i and IN to terminals I24 and l25 to which are connected through wires I26 and double-pole, double-throw switch I, switch 522, and wires Hill-L, the terminals i'i'i l, of field resistor Hll. Hence, when contacts 2i and are closed, winding 88 of relay it short circuited, and field resistor it]! is short circuited and the field current of exciter 3d is increased, and thereby the output voltage of alternator i8 is increased.

I have found that the system employing the several pieces of apparatus and the connections which I have described, give much improved operation over the arrangements of the prior art, regardless of what may be the actual manner in which the instantaneous values of voltage and current operate on the different parts of the apparatus. I will describe what I believe to be the manner of operation, Without, however, limiting my invention thereby.

The voltage of alternator 18 applied to Winding 4 tends to cause rotation of armature 9, and such rotation occurs at a frequency determined by the mechanical characteristics of the system including ballast wheel M and the value of the shunt resistance across the terminals of sup- 0 plementary winding TI.

The output D. C. voltage of exciter 84 depends on the average value of the exciter field current in its field I09 over a short period of time as a second, and this average value depends on the total part of an interval as one second during which rheostat lfll is short circuited by closing of contacts 2|, 22.

The various pieces of apparatus as rheostats IE3! and H9, springs l5 and 27, are adjusted so that as armature El vibrates, it maintains the alternator output voltage at a desired value. As above stated, the parts are adjusted to have armature t vibrate from about 200 to 500 times a minute.

L 3 If adjustable tap lll' is moved upward, or if spring 2'? is tightened, the vibration rate of armature t is increased. If tap MI is moved downward or if spring 2'! is loosened, the vibration rate of armature Q is decreased. Spring 91 is normally set to keep armature 96 up under normal operating conditions.

If after proper adjustments are made, the alternator output voltage increases a little, due perhaps to a little decrease in the load, the increased voltage applied to winding t tends to pull armature 9 farther and more strongly into line with pole pieces '5, 8, and this tends to keep contacts 21, 22, separated a greater total portion of an interval such as a second, and this decreases the average current through winding H38 and, therefore, reduces the alternator output voltage a little.

At the same time, every time that the contacts 2i, 22, are closed, they short circuit actuating winding 3 of relay R and armature GE) is pulled up and opens the short circuit across the lower part of resistor lid, which increases the resistance across supplementary winding :"i. This changes the magnetic reluctance of the magnetic circuit of frame 5, 6, and its integrated value over a short interval as a second, and tends to affect the position of armature 9. When contacts ii, 22, are open, the short circuit is removed from winding 28 and armature St is pulled down to close contacts 9t, 95, which short circuits the lower part of resistor Hi] and thereby decreases the resistance acr ss sup plementary winding ill and its integrated value over a short interval as a second, and varies the magnetic reluctance of the magnetic circuit of frame 5, 6, in the opposite direction.

If the alternator output voltage drops a little due perhaps to an increased load, the decreased voltage on winding tends to permii armature 53 to be retained in a position farther out of line with pole pieces '6, 8, and this Keep contacts 2|, 22, closed a larger total fractions part of a second. This tends to raise the average value of the exciter field current and thereby to raise the alternator output voltage. A the same time, the winding 88 of relay R is shor circuited while contacts 2!, 22, are closed, whicl releases armature 99 and opens the short circui across the lower part of resistor Hi1, and heme varies the equivalent magnetic reluctance whicl supplementary winding 11 applies to magnetic circuit 5, 6, both instantaneously and integrated over a second, and hence tends to vary the position of armature 9.

The combined effect of supplementary winding 11 with the various other parts of the apparatus as described, is found to give substantial improvement in the quality of regulation obtained, and the value of the current which can be handled by contacts 2|, 22, without damage thereto, and the size of alternator which can be satisfactorily regulated by such a vibrating regulator.

It will be apparent that I have provided a voltage regulator of simplified construction which is adapted to facilitate processes of production, and to regulate more efficiently alternators of larger size than it has been heretofore possible to regulate with vibrating regulators. It is to be noted that I am able to effect regulation of alternators up to 200 kw. by the use of only two electromagnetic switches or relays and only two pairs of contacts, and that the contacts 21 and 22 of the vibratory switch V not only short circuit the exciter field rheostat [0| but also the relay coil 88 which receives the voltage that exists across the terminals of rheostat liil at the moment contacts 2| and 22 separate. The relay R being thus energized short circuits the register H0 from the circuit of coil 11 thus affecting the operation of the vibrating switch carrying the contacts 2] and 22. The few parts and simple connections make the regulator comparatively inexpensive to produce and to maintain in operation.

I claim:

1. An improvement in a voltage regulating system of the type embodying an alternator, an exciter, and two electromagnetic switches one of which said electromagnetic switches controls the excitation winding of the other of said electromagnetic switches, and the last mentioned electromagnetic switch controls an auxiliary winding on said first-mentioned switch, said improvement consisting in providing said first-mentioned switch with a pair of vibrating switch contacts, connections for connecting an actuating winding of said last-mentioned switch in parallel with a rheostat in the field of said exciter and across said vibrating switch contacts, mounting means for mounting said vibrating switch contacts for small relative displacements, said first-mentioned electromagnetic switch including a principal actuating winding adapted to cause rapid relative movement of said vibrating switch contacts, means for normally urging said vibrating switch contacts into engagement, and further including an auxiliary actuating winding wound electromagnetically similarly to said principal winding and having a tapped resistor connected across itself, connections respectively between a tap of said resistor and one terminal of said resistor for connecting the same across contacts of said lastmentioned switch which are closed when its winding is actuated, connections between said principal actuating winging of said first-mentioned switch and the output terminals of the alternator, whereby variations in the output voltage of said alternator cause compensating variations in the field current of the exciter to regulate the output voltage of the alternator since said vibrating switch contacts are the only contacts employed to control the exciter without controlling said last-mentioned electromagnetic switch.

2. A system according to claim 1, said first-mentioned switch comprising a magnetic frame whereon said principal actuating winding and said auxiliary actuating winding is wound, and said firstmentioned switch being so arranged that said vibrating switch contacts separate when the voltage applied to said principal winding increases substantially.

3. A system according to claim 1, said firstmentioned switch comprising a rotatably mounted armature and a magnetic frame wherein said armature is mounted in magnetic relation, and mechanical inertia means mounted in mechanical relation to said armature for reducing the natural frequency of vibration thereof substantially below the synchronous frequency of said alternator, said vibrating switch contacts being mounted for relative displacement by movements of said armature.

MICHAEL DEBREY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,705,675 Paech Mar. 19, 1929 1,830,975 Ashbaugh et a1 Nov. 10, 1931 1,989,084 Debrey Jan. 29, 1935 

